Air-supported structure

ABSTRACT

THE ROOF OF AN AIR-SUPPORTED STRUCTURE IS PROVIDED A LIFT-COUNTERACTING EXHAUST CROWN TO COUNTERACT THE TENDENCY OF HIGH VELOCITY WINDS ACROSS THE ROOF TO &#34;FLY&#34; THE ROOF OF ITS BASE ANCHOR. AN AIR STRUCTURE IS ALSO PROVIDED WITH A DYNAMIC AIR DOOR WHICH CAN REMAIN OPEN CONTINUOUSLY FOR INGRESS AND EGRESS WITHOUT LOSS OF AIR PRESSURE   WITHIN THE STRUCTURE. THE AIR SUPPORTED STRUCTURE CAN BE A CIRCULAR DOME-SHAPED CONFIGURATION OR IT CAN BE OF RECTANGULAR VAULTED CONFIGURATION.

1 J. G. SCHNEIDLER 3,561,174-

AIR'SUPPORTED STRUCTURE 2 Sheets-Sheet 1 Filed Feb. 19, 1968 FIG 5 INVENTOR. JON G. SGHNEIDLER BYr ATTORNEYS 3,561,174 AIR-SUPPORTED STRUCTURE Jon G. Schneidler, 125 108th SE.,

Bellevue, Wash. 98004 Filed Feb. 19, 1968, Ser. No. 706,285 Int. Cl. E04g 11/04; F24f 7/06, 9/00 US. Cl. 52-2 9 Claims ABSTRACT OF THE DISCLOSURE Air-supported structures, wherein at least the roof assemblies are air-supported, have been proposed heretofore as substitutes for conventional structures. Their primary attractiveness is the apparent ability to provide large expanses of floor space, relatively unobstructed by roofsupporting columns or Walls, at substantially lower cost than conventional structures. In practice, however, airsupported structures have not gained significant acceptance. It has been found that the cost of anchoring structures required to establish air-supported roofs, particularly for the larger air-supported structures, has caused the overall cost of air-supported structures to increase to the point where the cost of conventional structures is no greater and is oftentimes much less. Furthermore, it has been found necessary to provide air-supported structures with complicated double-door air lock systems to permit ingress to and egress from the structure wtihout significant loss of air pressure. Such air lock systems have been found to be cumbersome to operate and generally unsuited for use in conveying materials into and out of the structure under conditions dictating relatively constant use of a doorway.

In contrast to the air-supported structures heretofore known, the present invention provides an air-supported structure that can be economically fabricated, including an anchoring structure for the air-supported roof assembly, and that provides a doorway that can be left open for ingress and egress without employment of cumbersome double-door air lock systems.

These and other advantages of this invention will become apparent from the following disclosure and the accompanying drawing in which:

FIG. 1 is an elevation view of a circular air-supported dome structure in accordance with this invention;

FIG. 2 is an end elevation view of a rectangular airsupported dome structure according to the invention;

FIG. 3 is a cross section taken along the line 33 of FIG. 1;

FIG. 4 is a cross section taken along the line 44 of FIG. 1;

United States Patent Ofiice 3,561,174 Patented Feb. 9, 1971 FIG. 5 is a detail section taken along the line 5-5 of FIG. 1;

FIG. 6 is a plan view of an exhaust crown structure for use in the present invention;

FIG. 7 is a detail section taken along the line 77 of FIG. 6;

FIG. 8 is a section view illustrating a preferred roof fabric anchoring assembly for use in the present invention;

FIG. 9 is a plan view of another exhaust structure for use in the present invention;

FIG. 10 is a detail section taken along the line 10-10 of FIG. 9; and

FIG. 11 is a diagrammatic view illustrating the internal-external air pressure control systems of the present invention.

One feature of the present invention is the provision of an air-supported roof structure having a lift-counteracting exhaust assembly. One of the major problems facing the designer of large air-supported structures, especially of the circular dome type, is that high velocity winds passing over the air-supported roof will create large lifting forces tending to fly the roof off of its base anchoring system. The lifting force created under high wind conditions can triple the structural loading on the roof material and on the roof anchoring system.

The exhaust assembly of the present invention functions by exhausting air through adjustable ports near the top of the air-supported roof structure to the extent necessary to effectively counteract the lifting force of high velocity winds. The exhaust assembly por-ts could be closed during normal wind conditions and would be opened as the sensed wind velocity across the assembly increased from a velocity of about 30 knots upward. The degree of opening may be governed by the sensed wind velocity, the ports being fully opened for a sensed wind velocity of knots or greater. By providing air-supported roof structures with exhaust assemblies in accordance with this invention, little or no increase in the structural strength of the roof material or the roof anchoring system would be required. This provision not only reduces the cost of the structure but also permits the use of relatively light weight roofing fabrics such that a minimum pressure differential will maintain the roof structure in an air-supported condition.

Another feature of this invention is the provision of an air-supported structure having a dynamic air doorway that remains continuously open for ingress and egress without loss of internal air pressure. Perhaps the major problem hindering the industrial development of air-supported structures has been the air lock requirement. To prevent major air loss and the danger of deflation present day structures employ a double set of doors with the vestibule between them serving as a static air lock. Only one door of the air lock can be open at a time, which presents an expensive, time consuming obstruction to handling significant volumes of material.

The dynamic air door of the present invention functions to direct streams of air through the Walls and ceiling of the accessway to effectively counteract the internal pressure of the air-supported structure such that no appreciable volume of air can leak through the accessway. Since the exhaust assembly function defined previously will permit use of lighter weight roof materials, the internal-external air pressure differential could be as small as about 0.020 p.s.i. Thus, the dynamic air door of this invention can be provided in entranceways large enough to accommodate trucks and rail traffic. For all practical purposes, therefore, the user can forget about his structure being air-supported inasmuch as he would be free to use the structure in virtually any manner that he would use a conventional structure.

Another feature of the present invention is an elevated air-supported roof structure anchoring system especially suited to anchoring a rectangular roof structure of vaulted configuration. By this feature, a series of parallel elongated roof spans could be anchored to elevated beams, each intermediate beam anchoring the adjacent sides of two parallel roof sections.

Referring now to FIG. 1, 3, 4 and 5, a circular dome embodiment of the present invention is depicted. In this embodiment, a base air-supported roof structure anchoring structure is provided to anchor a dome-shaped roof structure 12. The base anchor may be an upstanding wall as depicted or it may comprise a peripheral anchoring structure that would permit the roof structure to extend completely to the base surface. The dome structure contains an exhaust crown 14 at the peak thereof, and the base anchoring structure contains one or more dynamic air door structures 15 (one being depicted).

The exhaust assembly depicted is an exhaust crown comprising means providing a plurality of openings through the roof in the form of a radially slotted circular member 16; and means regulating the degree to which the slots 17 are opened in the form of a slotted circular disk member 18 journalled to a vertical shaft 20 and rotatable, responsive to means (not shown) sensing the wind velocity across the roof, by a suitable power source (not shown) such as an electric motor. A suitable weather-shielding canopy 22 may externally overlay the members 16 and 18.

In the depicted exhaust crown embodiment, the openings or slots 17 are opened and closed in unison by the disk member 18. An equally-suitable alternative is to provide a plurality of independently controllable air discharge mechanisms distributed around the roof peak. Such independently controllable mechanisms could be interrelated to open and close in unison, or sequentially, or otherwise, responsive to the sensed wind velocity.

The dynamic air door depicted comprises a walled accessway 30 provided at the top and sides with louvered sections 32 oriented to direct air streams toward the interior end of the accessway. Blower means 34 are provided to draw air inward from the ambient atmosphere through external grillwork 36 and to discharge air through the louvered sections into the accessway as shown by the arrows in FIGS. 3 and 4. Other suitable blower systems can be provided by which air streams are employed to maintain the required positive pressure within the airsupported structure by preventing air exhaust through the accessway.

Each accessway would also be provided with closeable doors, e.g. of the swinging or sliding type, so that the accessway may be closed off during periods of nonuse. Thus, the blower system associated with the accessway could be inactivated when the doors therein are closed and actuated, either automatically or manually, when the doors are open to expose the accessway.

Now referring to FIG. 2, rectangular areas can be enclosed by an air supported structure by providing a plurality of elongated air-supported roof spans 40 of vaulted configuration anchored by parallel, elongated elevated beams 42 supported by supporting columns 44 or the like. These elevated beams 42 may double as gutters for drainage. The side roof spans can terminate at elevated beams with side walls closing the gap between the beams and the base surface as shown, or the side roof spans could be extended to the base surface and anchored thereto. The latter alternative would eliminate the need for such side walls. This vaulted configuration requires conventional self-supporting end walls as shown which would normally include accessways, such as the type depicted in FIGS. 3 and 4. The exhaust assembly system also may be employed with the vaulted structure of FIG. 2 by providing such systems along the peak of each roof span. It may be the case, however, that the transverse width of each such roof span will be narrow enough that the high velocity wind lift forces will not generate such increased structural loads on the anchoring system and on the roof structure to require lift-counteracting exhaust assemblies.

The roof structure may be fabricated from any suitable material. A preferred lightweight, relatively high strength, relatively impermeable fabric is polyvinyl chloride impregnated and coated nylon sheeting. This fabric can be seamed to provide large surfaces that can be peripherally connected to the base anchoring structure in an air-tight manner. Roof structures thus constructed can be air-supported with an external-internal pressure differential as small as 0.020 p.s.i.

In the preferred embodiment, employing the abovementioned lightweight roofing fabirc or equivalent thereof, the exhaust crown structure is preferably provided with upper and lower annular roof fabric attachment rims 82, as shown in FIGS. 6 and 7. The upper rim may be an annular peripheral section of the upper circular disk member 16 and the lower rim may be an annular member peripherally enclosing the lower, rotatable disk members 18. The two rims have mating annularly-corrugated sections and opposing semi-circular annular groves inward of the corrugated sections. A circular opening of a diameter large enough to receive the lower rotatable disk member 18 is provided in the center of the roof structure and a rope or cable ring 84 is bound into the circular edge of the fabric. The exhaust crown is attached to the roof fabric by being lowered into the opening with the ring 84 fitted into the upper rim annular grove. The lower rim is then bolted, or otherwise suitably connected, to the upper rim on the opposite side of the roof fabric such that the ring 84 is retained in the opposing annular grooves as shown, and such that the roof fabric outward of the ring 84 is gripped by mating corrugations of the upper and lower rims as shown. Thus, when the air structure is filled with air to raise the roof, the exhaust crown will also be raised and will be supported entirely by the air-supported roof fabric and constitute a part of the roof structure.

The roof structure anchoring base 10 is preferably provided with one or more peripheral roof fabirc retainers of the type shown in FIG. 8. These retainers comprise an annular channel attached by its base 90a to an anchor base 92 and having a vertically upright circular outer leg 90b and an S-shaped upright circular inner leg 90c. A rope or cable ring 94 is bound into the circular outer edge of the roof fabric and inserted into the channel. The ring 94 is held in the channel by one or more spring clip plates 96 wedged between the outer leg 90b and the roof fabric such that the roof fabric immediately above the ring 94 is wedged against the S-shaped leg 90c.

By providing several concentric retainers 90 as shown in FIG. 8, two major problems can be prevented. The first problem, created in previously known structures when the roof fabric is replaced, is how to collapse, remove and replace the roof fabric when the structure is occupied with equipment such as lighting fixtures, heating and ventillating systems, and the operating equipment of the business occupying the structure without comletely shutting the buisness down and dismantling all overhead equipment before the roof is collapsed. The present invention prevents this problem by providing a retainer to which a new roof fabric can be attached after it has been stretched over the existing roof structure and the exhaust assemblies connected to the new roof fabric. The old roof fabric can then be removed without collapsing the entire roof since the new roof fabric will contain the pressurized inside air as the old fabric is removed, or the old fabric can be left in place if desired. Thus, there need be no disruption of the business housed within the structure during replacement of the fabric.

The second problem is how to thermally insulate the air-supported structure. By providing at least two retainers, a roof structure comprising two fabric roofs can be installed with a static air barrier between them.

In the preferred exhaust crown embodiment, suitable air velocity sensing means, such as an anemometer 100 in FIG. 11, drives a generator 102 which produces an electric current proportional to the wind velocities at the peak of the structure, thatthrough a suitable transducer means 104--actuates a motor 106 to open the exhaust crown to a predetermined degree. An independent pressure sensing means 108 regulates the blower system 110 to maintain the internal air pressure within predetermined limits as sensed by the means 108.

As an alternative to the wind velocity sensing system depicted in general by FIG. 11, an exhaust assembly may be provided that automatically opens and closes within predetermined external pressure limits that correspond to wind velocities. Shown in FIGS. 9 and 10 is a flapper type of exhaust assembly wherein valve flaps 120 are adapted to pivotally swing open in unison when the pressure differential across them creates an opening force sufficient to open the flaps against the action of spring means 122. When the air exhausted through the valve has raised the external air pressure suificiently to permit spring means 124 to reclose the flaps. Means 126 would also be provided to prevent the flaps from cycling between open and closed positions at wind velocities that fluctuate around that velocity required to trigger the assembly open. Thus, this alternative is sensitive to wind velocities such that air can be exhausted through the assembly to reduce the lifting force of the wind but does not have the variability of the exhaust crown embodiment. A plurality of the FIGS. 9-10 structures would usually be placed in the roof structure and could be designed to open at different wind velocities, however. Hence, the selective exhaust feature of the exhaust crown could be provided by the plurality of vents.

The air-supported structures of this invention also would be provided with suitable air compressing means and suitable ductwork to increase the air pressure within the structure to initially inflate the structure to raise the roof structure and to maintain the roof structure in a raised airsupported condition. Where required, suitable ventilation systems would also be provided and to the extent desired, the exhaust crowns provided in accordance with the invention could be included in the ventilation system. Such air also may be conditioned to remove dust and other foreign matter, and controlled in temperature and otherwise pursuant to conventional practice.

It is believed that the invention will have been clearly understood from the foregoing detailed description of my now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an air-supported structure comprising an air-supported roof and a base anchoring structure peripherally enclosing and anchoring the base of said air-supported roof, the combination therewith of a lift counteracting exhaust opening through said roof, means for sensing air velocity exteriorly of said air-supported roof, and means coupled to said air velocity sensing means for opening and closing said exhaust opening responsive to increases in wind velocity across said roof to discharge air through said exhaust crown system in suflicient amounts to reduce the lifting force of high velocity wind across said roof.

2. The air-supported structure of claim 1 wherein the exhaust opening providing means comprises a structure including a fixed multi-slotted member, and wherein the opening and closing means comprises a structure including a multi-slotted member rotatably mounted to the structure of said exhaust opening providing means adjacent to said fixed member and adapted to rotatably traverse the slots in said fixed member to open and close such slots.

3. The air-supported structure according to claim 1 including a dynamic air door system providing for ingress to and egress from the interior of said air-supported structure, said dynamic air door system comprising a structure providing an accessway communicating with the interior of said air-supported structure and with the ambient atmosphere, and means providing and directing pressurized air into said accessway in amounts sufficient to prevent air exhaust through said accessway so as to maintain a predetermined positive pressure within said air-supported structure.

4. The air-supported structure according to claim 3 wherein the structure of said dynamic air door system comprises side and top walls defining said accessway and having louvers therein oriented to direct air streams toward the inner end of said accessway; and wherein said means providing and directing pressurized air into said accessway includes air blower means adapted to draw in air external to said air-supported structure, compress the in-drawn air, and discharge the compressed air through said louvers.

5. The air supported structure of claim 1 wherein the means providing an exhaust opening include upper and lower annular roof fabric attachment rim members having interlocking corrugated sections adapted to be fastened against opposite sides of the roof fabric, and having opposing annular grooves inward of the corrugated sections adapted to retain a circular ring bound to the circular edge of the roof fabric.

6. The air supported structure of claim 1 wherein the base anchoring structure includes a plurality of elongated roof fabric retainers each comprising an annular channel with an upstanding inward side wall adapted to be engaged by the roof fabric with a ring bound to the base edge of the roof fabric laying in the channel such that a spring Clip member may be inserted into the channel containing said ring to wedge the roof fabric against its inward side wall.

7. The air supported structure of claim 1 wherein the means for opening and closing the exhaust opening responsive to increases in wind velocity include motor means for operating said closure means to open and close said exhaust opening, and transducer means interconnecting said air velocity sensing means and said motor means to actuate said motor means responsive to a sensed air velocity exceeding a predetermined minimum.

8. The air supported structure of claim 1 wherein the means for opening and closing the exhaust opening responsive to increases in wind velocity include pressuresensitive closure means for said exhaust opening, and restraining means acting on said closure means to keep said exhaust opening closed until a predetermined external pressure drop occurs responsive to a predetermined mini-/ mum air velocity and automatically eifects the opening of said closure means.

9. The air supported structure of claim 1 including internal pressure regulating means, independent of the means for opening and closing the exhaust opening responsive to increases in air velocity, comprising internal pressure sensing means, air blower means for pressurizing the interior of said air supported structure, and transducer determined minimum.

References Cited UNITED STATES PATENTS Brell 24-243,9

Vagschitz 522X Chase 137625.31X

HOtZ 522X 8 Gedney 522 Duquette 522 Imbertson 522X Babcock 5290 Cohen et a1. 521

FRANK L. ABBOTT, Primary Examiner S. D. BURKE III, Assistant Examiner US. Cl. X.R. 

